1. Technical Field of the Invention
The present invention relates to a computer chassis for free standing use or rack mounting and, more particularly, but not by way of limitation, to a computer chassis constructed with a modular mounting configuration for effecting ease and security in the installation or removal of components therein.
2. Description of Related Art
Early computer designs generally included a chassis with a plurality of individual components and assemblies mounted therein and connected to one another by means of wires, cables, brackets, nuts, bolts and the like. A major computer design advance occurred with the advent of printed circuit boards, integrated circuits and modular component assemblies. The printed circuit boards were, for example, formed of lightweight material and housed a myriad of components which were electrically interconnected with the component assemblies through wiring harnesses. The wiring harnesses and hard wire connections were subsequently replaced by technologically advanced connectors used for integrally coupling the individual components to each other and to other circuitry in the computer. Other advances, such as specially designed clips for minimizing electromagnetic interference (EMI), further enhanced the computers effectiveness and compatibility with other electronic systems.
In the design of electronic equipment, the use of connectors, modular components, and specialized hardware has permitted key components and printed circuit boards to be efficiently added and removed. Such ease in the addition and deletion of computer components and printed circuit boards has facilitated assembly repair, upgrade, and/or changes in functionality. Because the computers of today's complex business world may contain volumes of confidential information, one design aspect has always been security of the data stored in the computer system. Various chassis designs address such issues. For example, U.S. Pat. Nos. 5,154,456 and 5,162,976 (both assigned to the assignee of the present invention), teach security and locking systems for a computer chassis. Security of the disk drives and other computer components has thus been recognized as a valuable design aspect.
Computer reliability and serviceability are also valuable design aspects. Originally, a rule of practice in the maintenance of electrical circuitry, such as computer hardware, was that of always turning the power to the computer off before components or printed circuit boards were added or removed from the computer chassis or support frame. Recent innovations have addressed the desirability to insert and remove modular components and printed cards from electrical equipment, such as computer hardware, when the computer is electrically connected and operational, i.e. "hot." This is now possible for hot pluggable hard drives, and in these cases, the power may be disconnected from only the connector of the drive or modular component to be inserted and removed while allowing the adjacent components to remain "hot."
Removable computer components today include disc drives, drive cages, fans, power supplies, system I/O modules, processor boards, and other subassemblies. As referenced above, the removability of computer components allows for better overall serviceability of the computer system, which is a distinct advantage to both the user and the maintenance technician. A defective power supply in the main or central computer generally requires prompt replacement in order to limit downtime. It is for this reason that modular components and connectors facilitate prompt replacement and are thus popular in many computer designs. For example, U.S. Pat. Nos. 5,332,306 (Jul. 26, 1994) and 5,277,615 (Jan. 11, 1994), both assigned to the assignee of the present invention, teach disk drive mounting systems facilitating these removability features.
The modularity of computer systems is thus recognized as an important design consideration. As referenced above, modules can be removed and examined for operability or other purposes much easier than permanently mounted fixtures within a computer chassis. Because computers provide an integral part of most business operations, it is of utmost importance to maintain the reliability and integrity of the computer system. When the various elements of a computer can be easily removed in a modular form, they can also be replaced to maintain the operational status of the computer. They may also be replaced, however, to remove stored data. It is for this reason that information stored upon circuit boards or disk drives contained within the computer may need to be physically secured in such a way so as not to be readily available for access. Additionally, it is often important to know if any portion of a computer has been accessed or "tampered with" such as in those situations where sensitive data is maintained within some portion of the computer hardware.
The present invention provides such a security system by providing a modular computer chassis and associated specialized hardware specifically adapted for maximum efficiency and modularity with selectively restricted access thereto. Specialized EMI clips, printed circuit board card guides and locking systems are also provided to enhance these features. In this way, security and reliability are provided in a modular array capable of free standing or rack mount assembly.